This is the biggest one yet. Microsoft's professional extortion campaign - the third side of the same triangle it shares with Apple and Oracle - has finally hit Samsung. The two companies have signed a patent licensing agreement concerning Samsung's use of Android, in which a rumoured fee of $15 (!) per device will flow from Seoul to Redmond. Not entirely coincidentally, that's about the price of a Windows Phone 7 license.

Which themselves are copycats of other OSes too, and the track goes up to first OS ever made.
The earlier OSes makers just had a luck that 1) nobody has now and 2) allw them now to abuse to lock the situation in order to make this situation continues forever: they made their OSes while escaping patent troll was not even necessary.

These days, *they* are the patent trolls. Robin Hood became a Sheriff.